King v. Burwell is the second challenge to the Affordable Care Act to reach the Supreme Court, and it could lead to a widespread revision of the law. Oh, and the whole thing is basically one big nit-pick on just a couple little words in the ACA legislation.

First, a refresher on how Obama’s Affordable Care Act works: The law is set up to make health insurance accessible to everyone, especially low-income people. Americans who aren’t lucky enough to be covered through their workplace can purchase insurance through the private market (as always) or through state-run “exchanges.” On those exchanges, lower-income people can qualify for subsidies from the government to help cover the cost (and lots are — 87% of Americans who used the marketplace to buy a plan qualified for financial assistance).

When the law was written, everyone imagined that every state would have its own exchange. But, they don't: Most states — 34, to be exact — have been letting citizens use the exchanges created by the federal government. Not a big deal, right? People are still getting their subsidies and everyone is happy (well, mostly).

Not quite. The plaintiffs in King v. Burwell are arguing that all the people in those 34 states who use federal exchanges instead of state exchanges shouldn't get subsidies. Why? Because, in two places, the law's text specifically links those price-breaks to “state” (and not federal) exchanges.

The language’s intent seems pretty clear: Since the authors imagined all states would have exchanges, when they referred to "state exchanges," they must have meant to refer to something that would be made available to citizens in all 50 states. But, the wording is vague enough that it gives the law's opponents a real shot.

If King v. Burwell is upheld (and it could be), it could have disastrous consequences for a huge swath of people across the country — i.e. everyone who doesn’t make enough money to afford insurance otherwise. And, let’s face it: That’s a lot of us. As Slate explains, “Only the sickest people will stay [insured], which will cause insurance companies to raise prices for everyone, causing more people to drop out, and potentially throwing the insurance market into a spiral of death.”

For the well-being of the millions of people who enrolled in health-care plans through Obama’s insurance marketplace last year, here’s hoping those couple little phrases will be interpreted the way they were intenteded — not exactly how they were written.